Question

I'm really confused, can somebody help me please?
A farmer plans to use 120 feet of fencing to enclose a rectangular region, using part of a straight river bank instead of fencing as one side of the rectangle, as shown in the figure.
(a) Find the area A of the region if the length of the side parallel to the river bank is twice the length of an adjacent side.
A = ______ft^2

(b) Find the area A of the region if the length of the side parallel to the river bank is one-half the length of an adjacent side.
A = ______ft2

Answer 1

C) Find the area A of the region if the length of the side parallel to the riverbank is the same length of an adjacent side.
A=____ft^2

Answer 2

So what you want to do for A is create a variable to represent the length of either the side opposite the river bank, or the other two sides. Does that make sense? Say for example, you let x be the two sides connected to the river.
We know that the side opposite the river is twice as long as these two sides. So that side is 2x. Now we only have to count the x's that we have. We have one on each of those two sides, and two for the side opposite the river. We can then set up an equation: x+x+2x=120, and solve for x.